A neurochemical investigation is being carried out which is designed to provide basic information about the regulation of brain function by corticosteroid hormones. An essential feature of this program is to provide information about the properties and role of the enzyme, corticosteroid acetyltransferase, which is responsible for the acetylation of naturally occurring glucocorticoids in the central nervous system. This enzyme is a constituent of glial cells. Corticosteroid acetyltransferase will be purified using the technique of affinity chromatography. The properties and mechanism of the purified enzyme will be investigated. A series of steroidal and nonsteroidal alkylating agents of corticosteroid acetyltransferase have been prepared for studying the active site of this enzyme. The effectiveness of these alkylating agents is markedly changed by small structural alterations which produce different steric and electronic effects.